Television broadcasters have long applied different overlays to video signals before they are transmitted. This may have started with subtitles and closed captioning. Overlays have expanded to include station or channel identification and other helpful signs and indicators. Some channels add banners, news tickers, scene descriptions, and personal name labels to a transmitted video. Recently compression systems have incorporated overlays as a separate component. This may result in overlays becoming used for more situations.
In order to make the subtitles or overlay more readable, the overlay is rendered in a very bright or a very dark color. In some cases, the overlay is placed outside the frame of the video. In some cases, the overlay is presented over a black or white box. In some cases, a subtitle is presented as white with a black outline or vice versa. All of these techniques are able to enhance the readability of the text or logo.